title: Age at onset of amyotrophic lateral sclerosis in China.
abstract: BACKGROUND
  For patients with amyotrophic lateral sclerosis (ALS), age at onset is not only a key factor for diagnosis and prognosis, but also a clue for exploring pathogenesis. Reports based on results from a single medical center suggested that the mean age at onset of ALS in China was earlier than in other developed countries. A larger, multicenter-based study is needed to confirm this finding.
  
  
  METHODS
  A registry-based study of ALS was conducted at 10 ALS centers of the Chinese ALS Association from March 1, 2009 to August 31, 2009. The demographical and clinical features of patients with ALS were collected.
  
  
  RESULTS
  Data from a total of 455 patients with ALS were available for analysis. The mean age at onset for the entire cohort was 52.4 ± 12.1 years. The peak age at onset was in the 45- to 49-year-old age group for women and the 55- to 59-year-old age group for men. The age at onset for patients from Guangzhou (a southern region) was significantly earlier than it was for patients from Shanghai (an eastern region) (t = 2.270, P = 0.025).
  
  
  CONCLUSIONS
  This investigation confirmed the earlier age at onset of ALS in China as compared with other countries. Further population-based case-control investigations of genetic and environmental factors are needed to identify the potential risk factors for Chinese ALS patients.
authors.affiliation: Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China.
authors.forename: M S
authors.initials: MS
authors.lastname: Liu
authors.forename: L Y
authors.initials: LY
authors.lastname: Cui
authors.forename: D S
authors.initials: DS
authors.lastname: Fan
mesh_terms: D000328:Adult; D000367:Age Factors; D017668:Age of Onset; D000368:Aged; D000690:Amyotrophic Lateral Sclerosis / Q000175:diagnosis / Q000453:epidemiology*; D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged
keywords: amyotrophic lateral sclerosis; clinical features; epidemiology; risk factor